Hector dewar



(No Model.)

- H. DBWAR.

ELECTRIC ARC LAMP.

Patented Mar. 22, 1892.

I a p 0 WITNESSES INVENTOR By I Attorney UNITED STATES PATENT OFFICE.

HECTOR DEXVAR, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO ALBERT TV. ROUNDS,OF SAME PLACE.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 471,234, dated March22,1892. Application filed September 15, 1891. Serial No. 405,768. (Nomodel.)

To aZZ whom it may concern:

Be it known that I, HECTOR DEWAR, residing at Boston, in the county ofSuffolk and State of Massachusetts, have invented certain Improvementsin Electric-Arc Lamps, of which the following is a specification.

My improvement relates to electric arc lamps, in which the are betweenthe positive and negative carbons is regulated and controlled by meansof main and secondary or shunt magnets, and I have in view the followingobjects for the improvement of such lamps: As such lamps are ordinarilyconstructed the electro-magnets are arranged upon the upper part of theframe or floor, and as the substance of the said frame or floor isfrequently used as a conductor of electricity in forming short circuitsfrom one part of the lamp to another it happens that where twoindependent electro-magnet-s are employed in the regulation of the lampand are secured to said frame or floor magnetic circuits are formedbetween the poles of the said two magnets, which very materially disturbthe magnetic circuits of each electro-magnet and atfect their workingproperly, and in lamps employing independent main and secondary or shuntmagnets having a lever between them provided with armatures, whicharmatures are associated one with the main and one with the secondary orshunt magnets, it has been customary to make the said lever in one pieceof magnetizable material, which soon becomes magnetized and itssensitiveness to the lines of force or attraction of the poles of theelectro-magnets is impaired.

It is very desirable in are lamps that the same lamp be so constructedthat it can be placed in circuits of different amprage-for instance, toproduce a lamp which will burn in one circuitwith ten amperes and give alight of two thousand candles and which will also burn in anothercircuit with five amperes and give, say, a light of eight hundredcandles without removing the coils or any part of the lamp. The arelamps now in commercial use have their magnets wound for a specifiedamprage and candle-power, different lamps being used in circuitsdiffering in amprage. By my invention I am enabled to effect thisresult.

My invention consists in so adjusting and proportioning the relations ofthe current passing through the lamp to the main and secondary magnetsand their armatures and of the relations of the said magnets and armatures to each other that the are between the carbons is regulated andmaintained under the wide differences of amprage men tioned.

To this end Figure 1 represents a side elevation of the upper portion ofan electric' arc lamp, showing the floor or platform upon which are themain and secondary or shunt mag nets, the standard supporting thearmaturelever, and the carbon rod. Fig. 2 is a plan View of the same.Fig. 3 is a sectional view on no a: of Fig. 2, and Fig. at is asectional view on line y of Fig. 2.

A A are the main magnets, and B B are the secondary or shunt magnetssecured to the floor or platform a, but insulated therefrom by theinsulating material Z and n.

As the electro-magnets are insulated and connected to the floor in thesame manner, a description of one will be sufiicient, thereference-letters being the same for both.

I provide slots 19 p in the floor a, as shown, extending centrally ofthe electromagnets Extending longitudinally from the outside of thefloor through the slots 19 p are the screws jj, having a bearing m attheir ends and a collar 7t, which bears on the outer face of this slot13. A thin strip of insulating material Z is interposed between theheels of the electromagnets and the floor at, having a square projectingunder portion 5 integral therewith, which fills the cross-section of theslot 19, as shown in Fig. 3, but does not the longitudinal section, asshown in Fig. i, there being slotspace at each end thereof. The portion8 serves as a nut, the screw j extending through it. A strip '22 ofinsulating material under the floor a extends parallel with the piece Z,having holes at each end, through which pass the screws 0 0 into thecores of the electro-magnets. The holes in the floor a, through whichthe screws 0 0 pass, are larger than the screws, and are slottedparallel to the slots p p.

The standard L is secured to the floor a and has pivoted at its upperend the lever F, made of nonunagnetizable metal, as brass, and has uponits ends armatures H and G of magnetizable metal, as soft iron. I haveshown them as being adjustable to and from their pivot by means ofscrewsfand e, as shown in the application of D. Houghton, Serial No. 378,184.

By making the lever F of non-magnetizable material I prevent thedisturbance in the opposite armatures which is occasioned by its beingof iron or other magnetizable material, the molecules of the armaturesbeing free from all influence except that exercised upon them by thecores of their own magnet-spools, and are free to become oppositelypolarized of the screws f and e, and in the second way thereto andthereby.

The insulation Z s 'n entirely separates the electro-magnets A A and B Bfrom each other, so that there is no possibility of amagnetic circuitbeing formed between their separate cores through the floor a. Tofurther the v magnetic separation between the said electromagnets, Iconstruct the floor a of non-magnetizable material, as brass, and formagnetic separation this would in most cases be sufii cient; but as Iwish to separate them electrically as well I employ the insulation Z sn.

In carrying out the second part of my inventionthat of providing a lampwhichcan be used in circuits of widely-different amprage, ashereinbefore statedI have shown in the drawings means which I will nowexplain. It is well understood that when a certain current is passingthrough electro-magnets which have armatures arranged opposite theircores a certain and well-defined effect is produced upon a carbon rodthrough the clutch mechanism intermediate of the said magnets and carbonrod. The entire lamp is constructed to produce the said effect, and anydifference in current beyond a slight variation will not operate thelamp. To permit any wide change of current-say from ten amperes to fiveor vice versait becomes necessary to alter the adjustments of the partsof the lamp to each other or to take out portionssuch as coils which arewound for a certain definite current-and introduce others suitable tothe current to be used. The means employed by me are such as to continuethe lamp with all its parts intact and without the substitution of any.Itis known that an armature which is adjusted to its magnet-core toenable it to perform its work has to be adjusted closer to the said corein case the currentis weakened. I am not aware that this principle hasbeen applied to electric lamps-21 a, to secure the same work by theclutch mechanism under a weak current that has been performed by astronger current by means of adjusting the relations of the armature andmagnet to each other. Referring to the drawings, I show two independentways of accomplishing this result-first, by adj usting the armatures totheir cores, and, second, by adjusting the eleetro-magnet cores to theirarmatures. In the first way the armatures are moved toward or from theircores by means the 'electro-magnets and cores are brought nearer to orcarried farther from their armatures by the screws j, which have theabutments m, and the collar is, which prevents them from advancing orreceding. By turning the screws j in the insulating-nut stheelectromagnets are adjusted to their armatures, as described. I may, ifI choose, use both ways in the same lamp.

By the means described I have been able to place my lamps in circuitsusing such widely-differing a-mprage as five and ten amperes,respectively, and use them commer cially.

I claim- 1. In an electric-arc lamp, the combination of a non magneticfloor, mag-nets secured thereon, an insulating-stri p between themagnets and the floor, havinga depending block,

and adj usting-serew mounted in the floor and passing through the saiddepending block.

2. In an arc lamp, a brass base-plate, a main magnet, the cores of whichare connected by a bar or shoe insulated from the base-plate, and asecondary magnet, the cores of which are connected by a shoe or bar,insulated from the base-plate, in combination with a brass frame orbridge piece and a frame of non-magnetic 9 GEO. WILLIS PIERCE, V. M.BERTHOLD.

